Thanks for the explanation.
Originally Posted By: lespauled
The 13-pin is for Roland-type boxes, like (in my case) the Roland GR-55. The 2 little toggles control the Roland device. One switches patches on the GR-55, the other 3 position mini-toggle switches between 13-pin output only, acoustic output only, or a mix (middle position).

If you have a mixing board, or a usb interface like a Focusrite, you can plug in all three and control what comes through on the guitar.

It's really an incredible guitar.